Spring-jack connection



June 25, 1929. P. G. EDWARDS SPRING JACK commcnon Filed. May 4, 1928 INVENTOR z? G'Edwaz'ds Patented June 25, 1929s UlhllTE STATES PATET OFFECE.

PAUL G. ED'LVARDS, GE BLOOMFIELD, "NEW JERSEY, ASSIGNOR TO AMERICAN TELE- PHUNE AND TELEGRAPH GOMPANY, A CORPORATION OF NEW YORK.

SPRING-JACK CONNECTION.

Application filed May 4, 1928. Serial No. 275,106.

This invention relates to telephone spring elevation of the improved spring jacks; Fig. jacks, and more particularly to interconnect- 3 is a top plan view of said spring jacks; Fig. ing the springs of such jacks. l is a sectional View taken on the line 4c"4:

in practice, distant telephone stations are of Fig. 1 and -l-4l of Fig. 3. Fig. 5 is a dia- 5 interconnected by means of toll lines which grammatic view of the circuit connections of 60 are relayed through central oilices intermedithe ii'nproved arrangen'ient and Figs. 6 and 7 ate the telephone stations to be connected. Tn are further diagrammatic representations of estab ishing the connection between the disthe former and improved arrangements, retant telephone stations therefor, the toll lines spectively.

have included in their circuit considerable in the drawing, the numeral designates 65 equipment including test boards which are sheet metal. plates which are adapted to be provided with spring jacks whereby they secured to the rear face of a switchboard by may b t t d T mgg i g j cks ar ade means of screws which pass through openup of usual elements, including springs and ings in, semi-circular lugs 6, 6. Each of the their contacts, and the toll lines have been pla is pr vided ith a C cular opening 7.0 heretofore connected in series through such through which. the tubular sleeves 7 extend. springs and contacts. The springs and their The distance of such extension may correcoutacts present considerable trouble due to $1 0 1 Cl to the thickness of the insulating blocks contact resistance, wearing out, corroding, (not shown),through which they pass so that and other defects, which occur between these the outer ends of the sleeves terminate near elements. The toll line will cease to functhe outer vertical surface of such blocks to lion when any of these troubles occur in the permit the insertion of plugs in such sleeves.

circuit. It will be apparent that with the in- 'The inner ends of the sleeves 7 are suitably grease in the length of the toll line there will attached to the metal plates The plates 5 be corresponding increase in the number of rm portions of frames which support the so springs and their contacts connected in series lements of the Spring jack. The remainder relation in said toll line so that the trouble f Such frames, as indicated by the numeral which. may arise from these elements becomcHd at right angles therefrom, and may ing defective will be augmented in accord be of h us al character of well-known conance with the length of the line. For in- StIUOtiOIL is.) stance, a toll line from New York to Chicago A on a t spring iS associated With each includes approximately 800 springs and assoframe and iS Secured to one end thereof by (fifliefl contacts. means of screws 10. The contact springs may i is therefore an object of this invention to be provided with extensions which form terirovide a spring acl; which will reduce the minal lugs 12 to which electrical conductors 90 probability of circuit troubles due to conmay be attached. The lugs are held in positact resistance and other defects between the t 011 the j frame YS 11ml Suitelcments of the spring acl; practically to able means are provided to properly insulate Zero. the terminal lugs from the jack frame. The Another object of the invention is to ac contact springs are placed in a longitudinal 95 complish this result without changing any position in the jack frame and are of substanof the circuit features or the appearance or tially flat character, with bent ends 13 which use of the standard spring jacks. are connected to the main portions by interlt is a further object to provide a spring mediate angular shoulders. The bent ends jack of simple construction and economical are adapted to co-operate with plugs when 100 manufacture. they are inserted in the sleeves 7. The These and further objects will be apparent springs 9 which are mounted in pairs in paralfrom the following description, when con: lel relation in jack frames are each provided sidered in connection with the accompanying with arms or projections 14 which extend at drawing, in which one embodiment of the inright angles therefrom and make contact with 05 vention is illustrated. the flat surface of a companion spring. Referring to the drawing, Figure 1 illus These arms or projections extend in opposite trates an elevation of a plurality of plates directions from their respective springs and for spring jacks which are attached tothe are similarly related to each other. Openin s are of a switchboard, 2 is a side 15 are pi'fovided the jack a to perniit no tion. with each other.

the passage of the arms or projections there through so that they make contact with the parallelcompanion contact spring Each arm or projection carries a contact point 16 which normally bears against a contact piece 17 formed on the spring 9 of the companion parallel spring, so that a pair of such springs will be normally connected by means of their respective arms or projections in parallel relathis parallel connection between the pairs of springs will reduce circuit problems to a minimum, for if the contact between one arm or projection and the contact spring against which it bears for any reason becomes delective, then the contact between the other arm or projection and its contact spring will. be maintained. It there is a probability oi trouble of one per hundred for each set of con tacts, the probability for the former series arrangement is two per hundred. For the improved parallel arrangement, above described, the probability of trouble would be one per ten thousand. The probability 0]": trouble between the contacts of a spring jack by means oil the improved arrangement is thus reduced in a very large ratio.

The advantages of the improved arrangement are more clearly illustrated in the diagrannnatic representations shown in Figs. 6 and 7. In Fig. 6, which shows a former arrangement, it will be noted that the spring jacks 9 are connected in series relation. defective condition between either the upper or lower spring 9 and the jack associated therewith to complete the circuit, for instance throngh the plugs of a patching cord inserted in each jack and over the conductors 18, would render such circuit in operative. If a detective condition between the contacts of one spring ack causes a line to be inoperative, it will readily be understood that the chances of defects arising through the many spring jacks which are serially connected in the toll line would greatly increase the inopcration thercol.

Fig. 7 illustrates the principle of the new arrangement as applied to Fig. 6. It consists essentially of connecting each set of con tacts of s jirings 9 in parallel with line 18, and of causing these sets of contacts to be broken simultaneously, upon .the insertion of a plug in either jack, by mechanically interlocking the moving springs 9, shown for instance by the connection of a strip of insulation thereto. It will be obvious that a detect in one or the other of the sets ofcontacts will not affect the operation of the line over conductors 18. Fig. 7 is electrically equivalent to Fig. 5, the latter showing the actual contact arrangement and the former illustrating its operation as compared with the present arrangement.

it will be apparent that I hat is claimed is:

1. A spring jack comprising a frame, a pair of parallel contact springs extending longitudinally thereon and each adapted to be operated independently by plugs, and extensions carried by each spring normally contacting with the other spring whereby a parallel connection is made over conductors connected to said springs.

2. A spring jack comprising a frame, a pair of parallel contact springs extending longitudinally thereon and each adapted to be operated independently by plugs, said springs being adapted to be moved laterally, and extensions carried by each spring and normally contacting with the other spring, said extensions breaking contact with the springs upon the lateral movement thereof.

3. A spring jack comprising a frame, an

upper contact spring and a lower contact spring extending longitudinally in the frame and in parallel relation with each other and each adagted to be operated independently by plugs, a perpendicular extension from each spring in normal contact with the other spring, said springs being movable laterally to break the contacts of the extensions there with.

1-. A spring jack comprising a frame, an upoer contact spring and a lower contact spring extending longitudinally in the frame and in parallel relation with each other and each adapted to be operated by plugs, a perpendicular extension from each spring in normal parallel contact connection with the other spring, either spring being movable laterally to simultaneously break the contacts ofboth extensions.

5. Aspring per contact spring and a lower contact spring extending longitudinally thereon in parallel relation, and arms carried by each spring in normally parallel contacting connection with the other spring, said arms extending in op posite directions to each other from their respective springs and being similarly related to each other.

6. A spring jack comprising a frame, a pair of contact springs extending longitudinally thereon in parallel relation and each adapted to be operated independently by plugs, and arms carried by each spring normally contacting with the other springs, said arms extending in opposite directions to each other from their respective similarly related to each other and either spring being movable laterally to simultaneously break the contacts of the extensions.

In testimony whereof I have signed my name to this specification this 2nd day of May, 1928.

PAUL G. EDKVARDS.

'ack com arisin a frame an 11 springs and being i 

